Applicants' prior Application Publication No. U.S. 2007/0255379, discloses an intravascular neurostimulation device and associated methods for using the neurostimulation device to stimulate nervous system targets. In various ones of the disclosed embodiments, electrodes positioned within a blood vessel (e.g. a jugular vein, superior vena cava, or inferior vena cava) are used to transvascularly stimulate nervous system targets located outside the vasculature. Such stimulation can be used to lower heart rate and/or control blood pressure as a treatment for hypertension or heart failure (HF). Anchors are described for maintaining the electrodes in contact with the blood vessel wall. The anchors include structural features that allow the anchor to radially engage a vessel wall. As described, a hand, sleeve, mesh or other framework formed of one or more shape memory (e.g. nickel titanium alloy, nitinol, thermally activated shape-memory material, or shape memory polymer) elements or stainless steel, Elgiloy, or MP35N elements may be used as an anchor. In use, the anchor (with the electrodes thereon) may be released from a sheath within the blood vessel, such that the anchor expands into contact with the blood vessel and thereby biases the electrodes against the vessel wall.
Applicants' co-pending application Ser. No. 12/413,495, filed Mar. 27, 2009 and entitled SYSTEM AND METHOD FOR TRANSVASCULARLY STIMULATING CONTENTS OF THE CAROTID SHEATH discloses a method for transvascularly stimulating the vagus nerve and other nervous system structures, such as those disposed within the carotid sheath. The disclosed method includes advancing an energy delivery element, which may be an electrode, into an internal jugular vein, retaining the energy delivery element in a portion of the internal jugular vein contained within a carotid sheath, and energizing the energy delivery element to transvenously direct energy to target contents of the carotid sheath external to the internal jugular vein. The energy may be directed to a carotid artery within the carotid sinus sheath, and/or to a carotid sinus nerve or nerve branch within the carotid sinus sheath, to nerve branches emanating from carotid artery baroreceptors, and/or to a vagus nerve or associated nerve branch within the carotid sinus sheath. In some of the disclosed embodiments, a bi-lateral system is employed, in which a second electrode or other second energy delivery element is introduced into a second internal jugular vein and retained in a portion of the second internal jugular vein contained within a second carotid sheath. The second energy delivery element is energized to direct energy to contents of the second carotid sheath external to the second internal jugular vein.
The right vagus nerve primarily innervates the sinoatrial node of the heart; stimulation of this nerve increases the duration of the cardiac cycle. The left vagus nerve primarily innervates the atrioventricular (AV) node of the heart; stimulation of this nerve slows AV conduction. The assignee of this application conducted anatomical studies on human cadavers to investigate the relative location of the right vagus nerve to veins that could provide sites for transvenous vagal stimulation to reduce heart rate and blood pressure. The findings strongly support the rationale for a transvenous approach to vagus nerve stimulation in the human. The right vagus nerve and its cardiac branches closely and reliably course directly alongside the largest veins in the neck and superior mediastinum, namely the right internal jugular vein, right brachiocephalic vein, superior vena cava, and azygotic arch. Additional studies performed by this assignee support the use of electrodes against the posterior wall of the mid- to cephalic superior vena cava to control heart rate and blood pressure, such as for treatment of heart failure.